Acronym	rapsady
Name	retroantiprismatosnub dishecatonicosachoron
Circumradius	(1+sqrt(5))/2 = 1.618034
Vertex figure	©
Colonel of regiment	(is itself not locally convex, but no other uniform polychoral member known: by cells: pap seside sirsid rapsady 1440 120 120 )
Face vector	2400, 21600, 22080, 1680
External links

As abstract polytope rapsady is automorph, thereby interchanging the roles of pentagons and pentagrams, resp. those of seside and sirsid.

Rapsady is the only known non-prismatic uniform polychoron, which uses snubs for cells. In fact, this polychoron can be visualised as having 144 rings of 10 paps each, filled inbetween by sesides and sirsids.

As it happens, the pairs of pap vertex figures within this polchorons vertex figure have along their longer side the same dihedral angle as do have the pairs of pap vertex figures within the sisp vertex figure. Therefore both vertex figures have the same circumradius and thus the polychora too have the same circumradius.

Incidence matrix

2400 |    6    12 |    3    3    9    9    6 |    6   3   3
-----+------------+--------------------------+-------------
   2 | 7200     * |    1    1    1    1    0 |    2   1   1
   2 |    * 14400 |    0    0    1    1    1 |    1   1   1
-----+------------+--------------------------+-------------
   5 |    5     0 | 1440    *    *    *    * |    2   0   0  {5}
   5 |    5     0 |    * 1440    *    *    * |    0   1   1  {5/2}
   3 |    1     2 |    *    * 7200    *    * |    1   1   0
   3 |    1     2 |    *    *    * 7200    * |    1   0   1
   3 |    0     3 |    *    *    *    * 4800 |    0   1   1  (individual {3}, pairing as non-regular compounds)
-----+------------+--------------------------+-------------
♦ 10 |   10    10 |    2    0    5    5    0 | 1440   *   *  pap
♦ 60 |   60   120 |    0   12   60    0   40 |    * 120   *  seside
♦ 60 |   60   120 |    0   12    0   60   40 |    *   * 120  sirsid

2400 |    6    12 |    3    3    9    9    6 |    6   3   3
-----+------------+--------------------------+-------------
   2 | 7200     * |    1    1    1    1    0 |    2   1   1
   2 |    * 14400 |    0    0    1    1    1 |    1   1   1
-----+------------+--------------------------+-------------
   5 |    5     0 | 1440    *    *    *    * |    2   0   0  {5}
   5 |    5     0 |    * 1440    *    *    * |    0   1   1  {5/2}
   3 |    1     2 |    *    * 7200    *    * |    1   1   0
   3 |    1     2 |    *    *    * 7200    * |    1   0   1
   6 |    0     6 |    *    *    *    * 2400 |    0   1   1  (non-regular compounds of 2{3})
-----+------------+--------------------------+-------------
♦ 10 |   10    10 |    2    0    5    5    0 | 1440   *   *  pap
♦ 60 |   60   120 |    0   12   60    0   20 |    * 120   *  seside
♦ 60 |   60   120 |    0   12    0   60   20 |    *   * 120  sirsid